To calculate the percent composition of aluminum oxide (Al₂O₃), you'll need to determine the molar mass of the compound and then find the percentage by mass of each element in the compound.
-
Calculate the molar mass of Al₂O₃:
- Aluminum (Al) has an atomic mass of approximately 26.98 g/mol.
- Oxygen (O) has an atomic mass of approximately 16.00 g/mol.
The formula for aluminum oxide is Al₂O₃, which means it contains 2 aluminum atoms and 3 oxygen atoms.
\[ \text{Molar mass of Al₂O₃} = (2 \times 26.98 , \text{g/mol}) + (3 \times 16.00 , \text{g/mol}) \]
\[ = (53.96 , \text{g/mol}) + (48.00 , \text{g/mol}) = 101.96 , \text{g/mol} \]
-
Calculate the percent composition:
-
Percent composition of aluminum: \[ \text{Percent of Al} = \left( \frac{\text{mass of Al in Al₂O₃}}{\text{molar mass of Al₂O₃}} \right) \times 100 \] \[ = \left( \frac{53.96 , \text{g/mol}}{101.96 , \text{g/mol}} \right) \times 100 \approx 52.93% \]
-
Percent composition of oxygen: \[ \text{Percent of O} = \left( \frac{\text{mass of O in Al₂O₃}}{\text{molar mass of Al₂O₃}} \right) \times 100 \] \[ = \left( \frac{48.00 , \text{g/mol}}{101.96 , \text{g/mol}} \right) \times 100 \approx 47.07% \]
-
-
Final percent composition of Al₂O₃:
- Aluminum: 52.93%
- Oxygen: 47.07%
Thus, the percent composition of aluminum oxide (Al₂O₃) is approximately:
- Aluminum: 52.93%
- Oxygen: 47.07%
1 answer